The present invention relates in general to bleed elements in evaporative emission canisters for vehicle fuel systems, and, more specifically, to a deflector for retaining a carbon scrubber element.
Evaporative emissions systems are used in conjunction with the fuel systems of gasoline-powered vehicles to prevent release of hydrocarbon fuel vapors into the atmosphere. A typical carbon canister design uses a bleed emission treatment section to provide reduced emissions occurring during the diurnal (i.e., inactive) state of the vehicle. A large primary carbon bed handles the majority of fuel vapor during vehicle use and refueling. A bleed emission region close to the atmospheric vent uses an activated carbon scrubber element to capture low concentration hydrocarbon vapor from being expelled into the environment. Typically, the activated carbon element is held by a plastic molded tube generally open at both ends. This tube provides structure protecting the relatively fragile carbon element. An O-ring seal between this tube and the venting access of the mating shell has been used to assure a tight seal. Another separate molded piece is placed around the bleed tube to act as a bleed deflector or flow diverter so that vapors are routed through a zig-zag path to double back for entry into the bleed tube.
Very limited packaging space is available within the carbon canister. Therefore, it would be desirable to eliminate the separate bleed tube, o-ring seal, and any compliance media packed around the carbon element that is often used to protect the fragile element.